Signs of heat stress

Hi my plants suffered from slight heat stress leafs started to curl over.
I caught it early before leafs started changing colour.

I raised lights and switched from 600 watt to 400W. Also started just giving plants water and superthrive only.

Now it's second day after signs of heat stress and just water feed, now one plant has started turning yellow on edge of leafs slightly and also hve light yellow blodges.

Any ideas why?

Either lack of feed or delayed heat stress signs I'm guessing.

Thanks guys

Pics attached.